Cleanup: Remove unneeded forward declarations in webkit/plugins/.

webkit/plugins/ppapi/plugin_delegate.h

Index: webkit/plugins/ppapi/plugin_delegate.h
===================================================================
--- webkit/plugins/ppapi/plugin_delegate.h	(revision 110200)
+++ webkit/plugins/ppapi/plugin_delegate.h	(working copy)
@@ -27,11 +27,9 @@
 #include "webkit/plugins/ppapi/dir_contents.h"
 #include "webkit/quota/quota_types.h"
 
-class AudioMessageFilter;
 class GURL;
 struct PP_NetAddress_Private;
 class SkBitmap;
-class Task;
 class TransportDIB;
 
 namespace base {
@@ -39,17 +37,12 @@
 class Time;
 }
 
-namespace content {
-class P2PSocketDispatcher;
-}
-
 namespace fileapi {
 class FileSystemCallbackDispatcher;
 }
 
 namespace gfx {
 class Point;
-class Rect;
 }
 
 namespace gpu {